Electrical circuits are used in a variety of environments that can present particular physical, chemical, and electrical factors for which the circuit must either be protected or be designed to endure. The present invention primarily concerns physical factors such as mechanical stress leading to fatigue, which in turn can cause a circuit malfunction by physically breaking or weakening a specific part of the circuit. A typical location for such malfunction is at or near the point of connection of a wire, lead, or other conductor to an electrical circuit. In circumstances where the wire and the connected-to circuit may move or rotate relative to one another, the wire may incur a concentration of mechanical stress and/or fatigue at or near the point of connection to the circuit. Mechanical stresses such as repeated bending or twisting, for example, can lead to a weakening of the wire until a break occurs.
FIGS. 1 and 2 provide examples of the problems addressed. In FIG. 1, lead 20 is connected to a printed circuit board 22 by a soldered connection 24. As lead 20 is twisted (as illustrated by arrow A), repeatedly bent (as illustrated by arrows B and C), or placed into tension or compression (arrow D), a concentration of stress occurs at or near the point of connection 26. Over time, as lead 20 is exposed to repeated mechanical cycles that provide for this concentration of stress, lead 20 may eventually weaken due to repeated deformation or cyclical movement. As a result, lead 20 will likely suffer a fatigue failure (or break) either at or near point of connection 26. Similarly, in FIG. 2, lead 20 is connected to printed circuit board 22 by a physical connector 28 that secures the connection of lead 20 by physically compressing or pinching lead 20 between crimping surfaces 30 and 32. Again, as lead 20 is subjected to a variety of forces as illustrated by arrows A, B, C, and D, lead 20 may weaken and eventually break due to repeated deformations at or near point of connection 34. An electrical connection more resistant to various forces and less likely to undergo fatigue failure is desirable.